The present invention relates broadly to electrically actuated valves and, in particular, to a valve having specific application as a pilot or control valve in hydraulic systems.
Electrically actuated valves are well-known in the prior art. Such valves include those that have solenoid actuated valve members. Such valves have discrete open and closed positions corresponding to energization of a solenoid coil or deenergization of the coil. Such valves are therefore either completely open or completely closed dependent upon the flow of current into the solenoid coil. While such prior art solenoid operated valves are useful in many applications, it is desirable to have a valve that is electrically controlled such that the valve member can be accurately positioned in a plurality of positions to provide fluid communication between selected ones of a plurality of fluid passageways. Such valves have particular application as pilot valves in hydraulic systems, specifically systems on tractors and other heavy equipment. The present invention satisfies this requirement in that it is a valve with a valve member having movement in proportion to electrical current flow. The valve member can thus be accurately positioned in an infinite number of locations by varying the direction and/or magnitude of the controlling current flow. When used as a pilot valve the present invention has the advantage of having an electronic closed loop control network. This electronic control has significant advantage over the prior art in hydraulic systems that are often subject to operation in a harsh environment. When used as a multiposition valve independent of a pilot or control function, the present invention provides a relatively inexpensive and accurately controlled multiposition valve.